Rheumatoid arthritis is a chronic destructive autoimmune disease associated with anti-immunoglobulins of the IgM, IgG, and IgA isotype. These antiglobulins are called rheumatoid factors (RF) because they are found at high levels in serum from rheumatoid arthritis (RA) patients. These antibodies are found to bind to the Fc portion of the patients' own Ig molecules.
Some IgM RF bind to only denatured IgG and are present in many non-rheumatoid disorders such as chronic infections, liver disease, neoplasia, and aging. These IgM RF are therefore not useful as definitive diagnostic tests for rheumatoid arthritis. They are speculated to serve as a mechanism for removal of circulating immune complexes and denatured IgG in all of the above disease conditions.
On the other hand, IgG RFs in rheumatoid arthritis patient serum appear to be true autoantibodies, since they self associate and produce pathogenic immune complexes. Little information is available on the function and specificity of autoimmune IgG RF. Inability to identify the particular autoantibodies has greatly impeded efforts to understand the etiology of the disease and to treat the disease. There is, therefore, substantial interest in finding ways to investigate the disease and understand the mechanism by which it operates, as well as finding methods to diagnose and treat the disease, particularly holistic methods to treat the disease.